Formation Of Transferrin (Tf) Protein Corona On Prussian Blue Nanoparticles And Its Drug Delivery Potential

Prussian Blue nanoparticles (PBnp) are a promising class of metal–organic nanomaterials for biomedical applications due to their biocompatibility, redox activity, and ability to encapsulate therapeutic agents. However, their clinical translation is limited by poor colloidal stability and rapid degradation in physiological environments, particularly in ionic buffers such as phosphate or bicarbonate. This study addresses these limitations by engineering a transferrin (Tf) protein corona onto PBnp surfaces and evaluating its effects on particle stability, degradation resistance, and drug-loading potential. PBnp were synthesized and coated with iron-saturated transferrin (holoTf) or unsaturated Tf under physiologically relevant conditions. Dynamic light scattering and zeta potential measurements confirmed successful corona formation, with PBnp@HoloTf exhibiting increased hydrodynamic diameter (162.6  2.6nm) and reduced surface charge (-5.96  0.67mV) compared to uncoated PBnp (119.71  10.16nm, -40.62  1.82mV). The PBnp@HoloTf system demonstrated increased resistance to degradation in phosphate and bicarbonate buffers, retaining over 85.77% of its IVCT absorbance after 24h at pH7.4, whereas uncoated PBnp underwent complete degradation and PBnp@Tf retained 10.79%. To understand this enhanced stability, PBnp were also incubated with iron-binding site amino acid residues (aspartic acid, histidine, tyrosine), which induced degradation under mildly alkaline conditions. This supports the hypothesis that unsaturated Tf destabilizes PBnp through Fe³⁺ chelation, while HoloTf acts as an inert barrier providing steric and chemical protection. Doxorubicin (DOX) loading studies revealed that PBnp@HoloTf can achieve up to 67.2% encapsulation at 2.5 µg/mL inputs and retain over 85% of loaded DOX after 24h. Preliminary drug release followed a dose-dependent trend consistent with the corona acting as a semi-permeable barrier. These findings demonstrate that transferrin corona engineering improves the physicochemical and functional performance of PBnp. The PBnp@HoloTf platform offers a scalable, biologically responsive system for non-covalent drug delivery with potential for receptor-mediated targeting. Future studies should investigate the molecular basis of the PBnp–Tf interaction and optimizing drug encapsulation and release kinetics under physiologically relevant stimuli.